To provide a crusher of high crushing efficiency provided with crushing blades which can be easily dismantled and removed and also easily restored to the original state without lifting rotating shafts when a crushing blade of lowered crushing capability is replaced and which can retain high rigidity close to an integrated type crusher, although having a split-type cutter.

A crusher includes at least one rotating shaft 20 or more rotated in a casing 10 of almost rectangular shape with a feed opening 11 for a material to be crushed formed on the upper section and a discharge opening 12 for the crushed material formed on the lower section and crushing blade rotors 25 set in the axial direction on rotating shafts 20 in a manner of moving close to fixed blades 30 and 35 in the casing 10. The crushing blade rotors 15 consist of flanges 26 provided at intervals on the rotating shafts 20, rib-shaped blades 27 mounted on the longitudinal direction on the rotating shafts 20 between the flanges and provided at intervals in the rotating shaft peripheral direction, and crushing blades 29 in the state of being mounted across the rotating shafts 20 on one side faces of the flanges 26 mounted replaceably by fastenings 28.